1. Field of the Invention
The invention pertains to the field of shutter blade position sensors for optical shutters. More particularly, the invention describes a means for sensing shutter blade position that is of particular applicability where the blades of an optical shutter are driven by a rotor magnet.
2. Description of the Related Art
The primary competing technology for shutter blade position sensing is optical and involves an infra-red (IR) emitter and receiver used to sense the presence (or absence) of the blade. However, this arrangement is complex and leads to the possibility of stray IR emission. This is particularly problematic given the fact that many shutters are used with or within IR based cameras, viewers, and sites. Thus, a technology that could avoid the use of IR in detecting shutter position is inherently useful and beneficial.